package com.zyf.apitest.transform;

import com.zyf.apitest.beans.SensorReading;
import org.apache.flink.api.common.functions.ReduceFunction;
import org.apache.flink.api.java.tuple.Tuple;
import org.apache.flink.streaming.api.datastream.DataStream;
import org.apache.flink.streaming.api.datastream.KeyedStream;
import org.apache.flink.streaming.api.datastream.SingleOutputStreamOperator;
import org.apache.flink.streaming.api.environment.StreamExecutionEnvironment;

/**
 * @author Malegod_xiaofei
 * @create 2021-12-27-21:00
 */
public class TransFormTest3_Reduce {
    public static void main(String[] args) throws Exception {
        // 创建执行环境
        StreamExecutionEnvironment env = StreamExecutionEnvironment.getExecutionEnvironment();

        // 设置并行度
        env.setParallelism(1);

        // 从文件读取数据
        DataStream<String> inputStream = env.readTextFile("D:\\Code\\IDEA-Project\\FlinkTutorial\\src\\main\\resources\\sensor.txt");

        // 转换成 SensorReading 类型
        DataStream<SensorReading> dataStream = inputStream.map(line -> {
            String[] fileds = line.split(",");
            return new SensorReading(fileds[0], new Long(fileds[1]), new Double(fileds[2]));
        });

        // 分组
        KeyedStream<SensorReading, Tuple> kayedStream = dataStream.keyBy("id");

        // reduce 聚合，取最大的温度值，以及当前最新的时间戳
        kayedStream.reduce(new ReduceFunction<SensorReading>() {
            @Override
            public SensorReading reduce(SensorReading value1, SensorReading value2) throws Exception {
                return new SensorReading(value1.getId(), value2.getTimestamp(), Math.max(value1.getTemperature(), value2.getTemperature()));
            }
        });

        SingleOutputStreamOperator<SensorReading> reduceStream = kayedStream.reduce((curState, newData) -> {
            return new SensorReading(curState.getId(), newData.getTimestamp(), Math.max(curState.getTemperature(), newData.getTemperature()));
        });

        reduceStream.print("reduceStream");

        // 执行
        env.execute();
    }
}
